Winter 2017-18: Discussion

MJohnston

Gaoth Laidir wrote: »

It's different for metars and synops. In metars, it's the prevailing visibility (the greatest visibility over at least 50% of the horizon/airfield), whereas in synops it's the lowest visibility in any one direction. Synop visibility will therefore tend to be lower than metars, on average, though in fog like today there is no difference.

Visibility is defined as the furthest distance at which an object can be clearly made out.

Thanks for that. I was wondering about the airports specifically because I guess they have runway lights that are going to be visible further out, and that's what would be more important to operations.

Gaoth Laidir

MJohnston wrote: »

Thanks for that. I was wondering about the airports specifically because I guess they have runway lights that are going to be visible further out, and that's what would be more important to operations.

In that case it's the RVR that's important

https://en.m.wikipedia.org/wiki/Runway_visual_range?wprov=sfla1

MJohnston

Gaoth Laidir wrote: »

In that case it's the RVR that's important

https://en.m.wikipedia.org/wiki/Runway_visual_range?wprov=sfla1

Is that what is used as visibility in the METARs?

George Sunsnow

http://www.telegraph.co.uk/travel/travel-truths/watch-what-its-like-landing-a-plane-in-thick-fog/

Gaoth Laidir

MJohnston wrote: »

Is that what is used as visibility in the METARs?

No. Both are used when the RVR goes below 2000 m.

e.g. This is Shannon's latest metar.

METAR EINN 111930Z 11011KT 0200 R24/1100D R06/0900D FG BKN001 BKN002 03/03 Q1023 NOSIG=

Prevailing visibility 200 metres
RVR on Runway 24 is 1100 metres and decreasing
RVR on Runway 06 (the other end) is 900 metres and decreasing.

Meteorite58

Winds from the SE strengthening overnight and look quite fresh along coasts initially and getting blustery overland too later in the day. Strongest winds off shore from the SW and W over open water . Winds ,although very high, probably feeling a bit stronger then normal I would think as not usually that strength from a SE'ly direction.

Looks like being very wet in the SW as the warm front initially seems to stall and then moves slowly across the country followed by a weak cold front. Temps seem to peak in the SW around 10C to around 6C further N. I am expecting a low cloud more or less continuously wet day here near Tralee, looks like most of the rainfall on mountains from lift.

County rebel

No expert on weather but it seems to be raining here in west cork since last August and we have more again tomorrow .is this to do with climate change we surely are getting more rain than say 30 years ago.sorry if this is in the wrong thread.

Meteorite58

Nice and sunny today in Kerry. Tracts of fog around the country showing up well on the NASSA Sat pic.

Meteorite58

The jet looks very strong over the country in the early days of next week with a strong W N/W airflow developing along the corridor between the Azores HP and the Northern LP.

Next Mon, Tues and Weds look very windy.

ECM 850 hPa winds













ECM 850 hPa winds

nagdefy

Meteorite58 wrote: »

The jet looks very strong over the country in the early days of next week with a strong W N/W airflow developing along the corridor between the Azores HP and the Northern LP.

Next Mon, Tues and Weds look very windy.

ECM 850 hPa winds

Fair wind chill with that, raw few days..

spoonerhead

Temperature in Dublin has gone from -1C at 10pm, to 3C at 1am. If this winter has taught me anything, it’s that this is one crazy country for weather

Gonzo

Currently -3C here. The past few days have been very cold in general. Wedesday's high here was 5C and Thursday's high was only 4C.

sryanbruen

LEVEL 1 Weather Alert - Be Aware- Rainfall Warning ...

https://www.boards.ie/vbulletin/showthread.php?t=2057829326

Rock Lesnar

Despite how the rain radar looks, there has been no rain in north meath thankfully

Meteorite58

That is some windy spell of weather from Monday with accompanying wind chill .

Meteorite58

Been watching next Tues/ Weds with interest. The ECM has been showing very tight isobars for a few days, looks like it could be very windy along Atlantic counties.





Note the high reading over the Kerry Mts, I have seen this on a number of these charts,I think they seem to give a peak reading for high terrain and not to be mistaken with wind speeds at the standard 10m.



850hPa winds

nagdefy

Meteorite58 wrote: »

Been watching next Tues/ Weds with interest. The ECM has been showing very tight isobars for a few days, looks like it could be very windy along Atlantic counties.

Looking at the weather on the 6 news and Tuesday had an average 3C over Ireland. That wind chill will make it feel well below freezing.

Meteorite58

nagdefy wrote: »

Looking at the weather on the 6 news and Tuesday had an average 3C over Ireland. That wind chill will make it feel well below freezing.

I can only imagine it will be skinning, especially on coasts or open countryside.

Gonzo

I have to admit, I'm really not looking forward to that wind chill next week, it's going to feel well below 0C for much of next week.

h7nlrp2v0g5u48

nagdefy wrote: »

Looking at the weather on the 6 news and Tuesday had an average 3C over Ireland. That wind chill will make it feel well below freezing.

Speaking of the weather on Six One News I see the weather charts got a bit of a make over. I must day I like the graphics. Sorry for going off topic but I said I would mention it in here. I saw them for the first time yesterday evening. Cloudy and grey here in Tipperary with a slight breeze and a nice nip in the air.

Oscar Bravo

Nice bright afternoon here in Castlebar with some sunshine breaking through in just light winds. feeling mild at 9 degrees.

amandstu

The early hours of the 18th ,does that look like a flooding episode on the South East coast of England?Kind of 1953 in reverse (from the South up)

I think tides will be pretty high ... it is 5 days away..


https://earth.nullschool.net/#2018/01/18/0000Z/wind/isobaric/1000hPa/orthographic=-39.16,63.39,823/loc=-10.849,53.483

Meteorite58

:eek:

Have to watch the evolution of this one for sure.



850 hPa winds

JCX BXC

There'd be a nice wind chill factor in that wind!

HighLine

GFS not looking too severe

nacho libre

It is noteworthy when it's the euro model showing the low that deep rather than the gfs. Although the ecm seems to be on its own in blowing up the low. The UKMO is not supporting it so far.

Meteorite58

nacho libre wrote: »

It is noteworthy when it's the euro model showing the low that deep rather than the gfs. Although the ecm seems to be on its own in blowing up the low. The UKMO is not supporting it so far.

Yes and it twas the ECM that first picked up Storm Dylan and had a fairly accurate track before the local models even picked it up and then they took a few runs to fall in line. The track of Dylan did drift a bit more North. Will see.

nacho libre

Meteorite58 wrote: »

Yes and it twas the ECM that first picked up Storm Dylan and had a fairly accurate track before the local models even picked it up and then they took a few runs to fall in line. The track of Dylan did drift a bit more North. Will see.

Well if the ecm is correct, then it'll probably be the wind that is the main concern, rather than snow at lower levels. It will be just feel really bitter in the heavy rain for most.

Meteorite58

Fast moving deepening storm if this comes to pass. Seen some Dutch interest about this as it is presently tracking across Ireland, the UK and then into Holland.

nacho libre

yes 90 mph gusts possible as it exits kent, no wonder they are taking note